The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
An automotive body unit with a sheet metal component which is reinforced with a reinforcing component of a fiber composite material attached extensively thereto is disclosed in DE 10 2012 203 888 A1. As formulated as a problem in DE 10 2012 203 888 A1, such hybrid components cannot be joined to other components in the region of the reinforcing component using joining methods conventional in vehicle construction, such as for example spot welding. DE 10 2012 203 888 A1 therefore proposes that the reinforcing component comprise at least one opening, such that the sheet metal component can be joined to another sheet metal component in the region of the opening using a conventional joining method. The sheet metal component is a sill panel reinforcing plate. The reinforcing component includes a carbon fiber-reinforced plastics material, the sheet metal component including a weldable iron material.
EP 2 689 882 A2 discloses a device and a method for friction stir welding. Here, two different metal sheets, i.e. one aluminum sheet and one steel sheet, are joined together. A filler material is used to close a joining crater.
US 2010/0089977 A1 also relates to friction stir welding of different materials. Here, an aluminum sheet is joined to a magnesium sheet, wherein combinations of copper, tin and zinc and other powders could strengthen the magnesium-containing and aluminum-containing friction stir weld material.
In automotive construction, it is advantageous, especially with regard to the body, for the latter to be particularly light. This saves fuel and thereby also reduces the emission of noxious gases, such as for example CO2. In different zones, the structural, i.e. body, components, need to be designed for very different loads. In this respect, the components have also to be produced in such a way as to achieve the most lightweight construction possible while losing as little material as possible. In regions which are exposed to particularly heavy loads, reinforcing measures may therefore also be provided. The components may for example be made from a basic element, and comprise thickened portions in places as reinforcing measures. “Tailored rolled blanks” are known. Tailored rolled blanks are however very complicated to produce, and in this respect also very costly. It is also disadvantageous that the entire component has to be disposed of in the case of just one rolling defect, no matter how small, since it then no longer meets requirements. It is however also conceivable to provide separate reinforcing elements on the basic element which may include fiber-reinforced plastics material. As has already been disclosed in DE 10 2012 203 888 A1, conventional joining methods are unsuitable. Reinforcing elements may be joined to the basic element using adhesively bonded joints, reinforcing said basic element in such a way that the anticipated loads may be absorbed by the vehicle body component. Adhesively bonded joints do not however allow the maximum possible joining power to be achieved. In this respect, additional mechanical joints are also necessary, which may however destroy the fibers of the fiber-reinforced plastics material, so negating the desired reinforcement. For example, reinforcing elements may be fastened to the basic element using rivets, which inevitably destroy the fibers in the region of the joint. In addition, shearing and cracking forces of the original joint may be reduced, wherein corrosion problems may also occur.
The article “Friction spot joining of aluminum AA6181-T4 and carbon fiber-reinforced poly(phenylene sulfide): Effects of process parameters on the microstructure and mechanical strength” (material and design 66 (2015), 437-445) relates to the possible joining of an aluminum sheet with a fiber-reinforced plastics material, reference also being made to EP 2 329 905 B1.
EP 2 329 905 B1 discloses a refilling friction stir welding method, in which a light metal sheet is joined to a fiber-reinforced plastics material. The friction stir welding device comprises a pin, a sleeve and a clamping ring. This device is intended to make it possible to close the friction welding crater with the friction stir welding device in the course of the welding process, wherein the fiber-reinforced plastics material is melted but the fibers should remain undamaged. Once rotation has stopped, the materials harden, such that the previously melted regions adhere to one another. In this respect, it is however explicitly stated that the known disadvantages of adhesive bonding are ruled out since no separate adhesive is used.